Safety head arrangement for fire extinguisher

ABSTRACT

Apparatus for dispensing a fluid medium under pressure is disclosed, including a container for storing the fluid medium and having a substantially tubular neck defining an opening. A control head is mountable within the opening and is movable relative to the longitudinal axis of the container to an outer position to seal the opening and to an inner position to vent the container. The control head is interlocked with the container by means of a bayonet type connection including a pair of inwardly extending flanges on the container and a pair of outwardly extending flanges on the control head. Inwardly and outwardly extending flanges are provided with mutually engageable abutment surfaces to constrain the control head against movement relative to the container when the control head is in its outer position.

United States Patent 1 Hansen June 26, 1973 [75] Inventor: Arne Hansen, New City, N.Y.

[73] Assignee: Walter Kidde & Company, Inc., Belleville, NJ.

[22] Filed: Nov. 10, 1971 [21] Appl. No.: 197,286

[52] U.S. Cl 169/31 R, 169/31 P, 220/40 R [51] Int. Cl. A62c 13/00 [58] Field of Search 169/31 P, 31 R; 220/40 R [56] References Cited UNITED STATES PATENTS 3,530,942 9/1970 Hansen 169/31 R 1,932,135 10/1933 Hall 220/40 R X 1,576,580 3/1926 Ellis 220/40 R 2,531,860 11/1950 ONeal, Jr 220/40 R 2,361,704 10/1944 Patterson 220/40 R X 2,942,754 6/1960 Young et al. 220/40 R 3,010,673 11/1961 Marconi 220/40 R X Primary Examiner-M. Henson Wood, Jr. Assistant Examiner.lohn J. Love Attorney-Harvey W. Mortimer et a1.

[57] ABSTRACT Apparatus for dispensing a fluid medium under pressure is disclosed, including a container for storing the fluid medium and having a substantially tubular neck defining an opening. A control head is mountable within the opening and is movable relative to the longitudinal axis of the container to an outer position to seal the opening and to an inner position to vent the container. The control head is interlocked with the container by means of a bayonet type connection including a pair of inwardly extending flanges on the container and a pair of outwardly extending flanges on the control head. lnwardly and outwardly extending flanges are provided with mutually engageable abutment surfaces to constrain the control head against movement relative to the container when the control head is in its outer position.

12 Claims, 3 Drawing Figures PATENTEDJUN 26 I975 FIG. 1

SAFETY HEAD ARRANGEMENT FOR FIRE EXTINGUISHER BACKGROUND OF THE INVENTION The present invention relates to apparatus for confining and dispensing a fluid medium under pressure, such as portable fire extinguishers and the like, and more particularly to a bayonet type arrangement for locking the control head of the fire extinguisher to the container.

Portable fire extinguishers of the type referred to herein have been heretofore provided with either a metal control head which is threaded onto the neck of a metal container or a plastic head which frequently is likewise threaded to the container. Such construction is particularly used in connection with smaller, portable fire extinguishers which carry a powdered extinguishing agent.

In applications where a low cost extinguisher is desired, such as portable extinguishers for home, car and boat use, extinguishers with metal heads have been found to be relatively expensive. This is because metal control heads are difficult and costly to produce due in part to the relatively high cost of machining the metal materials. Plastic control heads are less expensive to manufacture. However, it has been found that where a plastic head is joined to the container by cooperating threaded portions, the threads of either the control head or the container may be damaged or otherwise rendered ineffective if a misalignment occurs in the attachment of the control head to the container and the cooperating threaded portions become crossed. Such damage would require replacement of either the head or the container or both, making the cost of such accidental misalignment extremely high.

The present invention relates to extinguishers of the type having a metal container and a plastic control head and provides a bayonet type of connection between the control head and the container. In the preferred embodiment the control head is slidably mounted in the opening to the container. A portion of the container adjacent it opening is provided with a pair of laterally inwardly protruding lip portions or flanges positioned at diametrically opposite positions around the periphery of the opening. The control head is preferably provided with a cooperating pair of radially outwardly extending flanges to fit respectively beneath each of the fixed flanges on the container thereby to hold the control head in position. A pair of raised stop members is provided at one end respectively of each of the control head flanges to engage respective end portions of the fixed flanges to prevent the control head from rotating when it is in its operating position.

The control head is removed from the container by pressing downwardly on the control head to move the upper extremity of each of the stop members to a posi tion beneath the undersurfaces of the respective fixed flanges. In this position, the control head may be rotated approximately 90 to move its flanges out of alignment with the fixed flanges.

To affix the control head to the container it is only necessary to reverse the disengagement procedure outlined above. The control head is inserted into the container opening sufficiently to position the upper extremities of the stop members beneath the undersurfaces of the respective fixed flanges, and is then rotated approximately 90 until its flanges move into alignment with the fixed flanges. The control head may then be moved upwardly until the upper surfaces of its flanges abut against the lower surfaces of the fixed flanges. In this position each of the stop members protrudes above the upper surface of its adjacent fixed flange, thereby preventing further rotation of the control head. Under normal circumstances, fluid pressure within the container will insure that the control head remains in such raised position.

It is therefore an object of the present invention to provide a control head arrangement for a fire extinguisher having an improved threadless control head locking arrangement.

Another object is to provide a safety arrangement for a fire extinguisher having a bayonet type locking arrangement between the control head and the container of the extinguisher.

BRIEF DESCRIPTION OF THE DRAWINGS F or a further understanding of the present invention, reference may be had to the accompanying drawings in which:

FIG. 1 is a longitudinal view taken partly in crosssection of the upper portion of a preferred embodiment of a fire extinguisher equipped with the safety locking arrangement of the resent invention; and

FIG. 2 is a top view taken in cross-section along the line 2-2 of FIG. 1;

FIG. 3 is a view taken along the line 3-3 of FIG. 2.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is shown, by way of example, a fire extinguisher, generally indicated by reference numeral 10, having a preferably metal container or receptacle 11 for storing a fluid medium under pressure. The container 11 may be formed of a suitable metal such as stainless steel and is preferably provided with a domed end lla having an outwardly flared neck portion 12 defining an opening 12a.

A control head 13 is inserted into the opening 12a in such a way as to form a fluid-tight seal with an inner surface 16 on the neck. The sealing arrangement between the neck 12 and the control head may be accomplished in several ways; however, it has been found convenient to provide on the head 13 a sealing member, such as an O-ring 14, to engage the necks inner surface 16. For this purpose, the control head 13 is provided adjacent its lower end with an annular recess 17 to hold the O-ring.

The body of the control head 13 is preferably made of a plastic material such as polymerized formaldehyde, and is provided part way therethrough with a first axial bore 15 having an enlarged diameter lower end portion 21 for receiving a siphon tube 18. Tube 18 extends downwardly from the control head 13 into the container 11 where the chemical, for example an extinguishing agent in powder form, is stored. The upper end of the enlarged diameter portion 21 is formed with an inwardly tapered wall portion 22 to serve as a valve seat for a valve member 29 movable to control the charging and discharging of fluid from the container 11. A reduced diameter portion 23 of the bore 15 extends above the valve seat 22 and has an angled bend of substantially to be in fluid flow communication with a substantially laterally extending discharge passageway 24. The discharge passageway is formed within a protruding nose portion 46 of the control head, which may be pointed at the fire to be extinguished to direct the flow of exhausting pressurized fluid.

The control head 13 is further provided with a stepped axial bore 26 which is coaxial with the enlarged diameter bore 21 and extends inwardly from the upper end of the control head. The upper portion 27 of bore 26 is of the largest diameter, and a reduced diameter portion 28 is in fluid flow communication with the bore 15.

The valve 29 has a head 31 and a stem 32 and is mounted within the control head 13 so that the head 31 is positioned and can travel within the enlarged diameter bore 21. The stem 32 extends upwardly from the head 31 through the stepped bore 26 above the upper surface of the control head. The valve stem 32 therefore, extends along an axis common to the bores 21 and 26 and the siphon tube 18. An O-ring 33 is preferably mounted on the valve head 31 for engagement with the valve seat 22 to provide a fluid tight seal between the bore 2l and the discharge passageway 24.

A valve operating lever 41 is pivotally mounted at the top of the control head 13. Preferably, the lever 41 is mounted at pivot 42 on one side of the top portion of the control head and extends laterally across over the top or upper end of the control head and the protruding valve stem 32. In the embodiment illustrated the lever 41 extends laterally outwardly from the control head substantially coextensively with a handle 43 which is swaged or otherwise rigidly secured to the flared neck portion 12. The lever 41 may be provided with an outwardly protruding flange 44 which extends directly over the upper end of the valve stem 32 to engage the valve stem when the lever is pivoted in a clockwise direction, as viewed in the drawing. The valve 29, accordingly, may be operated when the lever 41 and the handle 43 are grasped in one hand and squeezed together.

In the preferred embodiment, the handle 43 is provided with an integral, substantially annular, support 51 the diameter of which is greater than the diameter of the flared neck 12 of the container 11. The support 51 is provided with an inwardly directed shoulder 52 which engages the undersurface of the-flared neck 12.

The upper periphery of support 51 is provided with a pair of preferably sector-shaped, laterally inwardly protruding lips 54, illustrated in FIGS. 2 and 3. These lips 54 preferably protrude inwardly from substantially diametrically opposite positions around the periphery of the support, and each is provided with a substantially flat lateral abutment surface 55 formed along its lower extremity. v

The control head 13 is provided with a pair of substantially sector-shaped laterally outwardly extending wing or flange portions 56. The flanges 56 are preferably integral with the control head 13, and protrude laterally from diametrically opposite positions around the periphery of the control head. Each of the flanges 56 is provided with a substantially flat lateral abutment surface 56a formed along its upper extremity and engageable with the abutment surface 55 of the lips 54 when the control head is in its operating position. The distance measured from the outermost point of one flange 56 through the center of the control head to the outermost point of the other flange S6 is determined to be only slightly less than the outer diameter of the support 51. Similarly, the radius of the curved outer periphery of each of the flanges 56 is slightly less than the radius of curvature of the inner circumference of the support 51. This arrangement will permit the control head with its flanges 56 to rotate freely within the space enclosed by the support 51.

In the preferred embodiment, the sector angle of each of the lips 54 is substantially the same as the sector angle of each corresponding flange 56. It has been found that a suitable sector angle for the lips and flanges is approximately 50", although the invention is not to be limited by such angle. This is merely preferred since the lips and flanges may therefore be provided with sufficient surface area to insure suitable stability for the control head in its operating position.

Each of peripheral area or spaces 50 located between the lips 54 of support 51, is preferably defined by a sector angle which is greater than the sector angle of the flanges 56 on the control head. The control head having the flanges 56 therefore may be easily inserted or removed from the opening 16 of the container 11 when it is turned approximately from the position shown in FIG. 2 to a position in which the flanges 56 have been moved out of alignment with the lips 54.

It should be noted that the invention is not to be lim ited by the provision of a total of four flanges for interconnecting the control head and the container. It is possible to provide only one outwardly extending flange member on the control head and one inwardly extending lip member on the support 51 without departing from the scope of the invention. The use of four flanges in the present configuration is preferred however, in that it offers superior stability to the control head while it is in its operating position.

It is also important to note that the useof substantially sector-shaped lip and flange members is by way of example only, and that other configurations having corresponding abutment surfaces for relative engagement in the operating position of the control head may be employed without departing from the scope of the invention.

Referring to FIGS. 2 and 3, each of the flanges 56 is provided at one end with a raised stop member or promontory 59. Each of the stop members is provided with an abutment surface 60 transverse to the substantially flat and horizontal abutment surface 56a. Each of the surfaces 60 preferably extends upwardly beyond the upper extremity of the corresponding lip 54, and is adapted to be engagable with a cooperating shoulder portion 61 formed atone end of each of the lips. The stop members 59 are positioned relative to the control head such that the abutment surfaces 60 face in substantially the same direction. Therefore, any attempt to rotate the control head in either direction while it is in its upper operational position will be inhibited by engagement of one or the other of the stop members 59 with the corresponding shoulder 61.

It will be understood that the invention is not to be limited by the particular embodiment described in connection with FIGS. 1-3. In an alternative configuration, for example, (not shown) one or both of the lips 54 may be apertured or recessed to receive corresponding projections located on the control head flanges. Such an arrangement would likewise serve to prevent rotational movement of the control head when it is in its upper operating position. The embodiment illustrated in FIGS. l-3 is preferred however, because it obviates any difficulties in aligning the lips and flanges in their locking position during insertion of the control head.

FIGS. 1 -3 illustrate the upper operational position of the control head 13. In this position the upper lateral surfaces of the flanges 56 abut against the lower lateral surfaces respectively of the lips 54 (FIG. 1), and the O- ring 14 cooperates with the inner surface 16 of the tubular neck 12 to seal the opening. When the container 11 is filled, pressure from the fluid within the container exerts an upward force against the bottom of the control head 13 thereby pressing the flanges 56 and 54 together.

In the operating position of the control head, the stop members 59 protrude upwardly beyond the upper lateral surface of the flanges 54, as seen in FIGS. 1 and 3. Rotational movement of the control head in either direction will be prevented by engagement betweenone or the other of the abutment surfaces 60 with its corresponding shoulder 61 on the lips 54.

To remove the control head from the container, it is only necessary manually to depress the control head downwardly relative to the container, until the upper end or extremity of each of the stop members 59 has been moved below the undersurface of the lips 54. The control head 13 may then be rotated approximately 90 in either direction without interference until the flanges 56 have been moved out of alignment with lips 54. It is then possible to lift the control head upwardly and away from the container.

The control head is locked to the container by reversing the process described above. It is first necessary to orient the control head in relationv to the lips 54 such that the flanges 56 are positioned within the spaces 50 formed between the lips. The control head is then manually pushed downwardly until the lower surface 62 (FIG. 1) of the flanges 56 engages the outwardly flared portion 53 of the tubular neck 12. The control head 13 may then be rotated 90 to move the lips and flanges 54-56 into alignment. Upward pressure may then be manually applied to move the abutment surfaces of the flanges together. Alternatively, the control head may be moved upwardly by a force applied to it by the pressure of the extinguishing agent within the container as the apparatus is being charged. In this instance, frictional forces between the periphery of the control head and the inner surface 16 of the tubular neck 12 are generally sufficient to hold the head in position until the container 11 is charged with sufficient pressure to move the control head into position.

The safety feature of the invention operates to vent fluid to the atmosphere before the control head is removed, or alternatively to indicate to the serviceman that the level of contained fluid or pressure is too high to allow safe removal of the control head. Upon downward motion of the control head sufficient to move the upper extremity of the stop members 59 below the undersurface of the lips 54 so that the control head may be rotated, the O-ring 14 is moved out of engagement with the surface 16 and breaks the pressure seal between the control head and the neck. Any pressure remaining in the container is thereby vented to the atmosphere before the control head is removed. If the extinguisher being serviced has not been completely discharged and a substantial pressure remains therein, the serviceman will known immediately from the force required to depress the control head. Under this condition, the serviceman will discharge the unit by operating the valve 29 before he proceeds to disassemble the extinguisher.

The invention thus provides a simple and inexpensive bayonet type mount for securing the control head to the previous container, and incorporates a safety feature for protecting individuals attempting to remove the control head under the usual fire extinguisher maintenance program.

What is claimed is:

1. Fluid medium dispensing apparatus comprising:

a container for storing the fluid medium under pressure and having a neck portion at one end defining an opening;

a control head mountable within said opening and having means thereon for sealing the opening, said .control head being movable relative to the container between an upper operational position in which said sealing means seals the opening and a lower venting position;

at least first and second mutually engagable flange elements connected respectively to the container and to the control head, each of said elements having an abutment surface engagable with the other to limit upward movement of the control head;

a pair of radially inwardly extending substantially vertical stop' surfaces formed on said container within said neck, said surfaces facing in opposite directions around the circumference of the opening in said neck;

a pair of radially outwardly extending substantially vertical stop surfaces formed on said control head, each of said outwardly extending 'stop surfaces being aligned with a corresponding one of said inwardly extending stop surfaces to constrain rotational movement of said control head when said control head is in said operational position.

2. The apparatus of claim 1 wherein the abutment surface of said first flange element overlies the corresponding abutment surface of said second flange element when the control head is in said operation position.

-3. The apparatus of claim 2 wherein at least one of said inwardly extending stop surfaces is formed as part of said first flange.

4. The apparatus of claim 3 wherein at least one of said outwardly extending stop surfaces is formed as part of said second flange.

5. The apparatus of claim 4 wherein one of said flange elements comprises a promontory, the stop surface of said one flange being formed on said promontory and having a portion aligned with the corresponding stop surface of the other of said flange elements when the control head is in said operating position.

6. The apparatus of claim 5 wherein said promotory is formed on said second flange member.

7. The apparatus of claim 6 wherein said container comprises a pair of said first flange elements protruding from substantially diametrically opposite positions along the periphery of said neck. 1

8. The apparatus of claim 7 wherein said control head comprises a pair of said second flange elements .protruding from substantially diametrically opposite positions along the periphery of said control head.

9. The apparatus of claim 8 wherein each of said flange elements comprises a substantially sector shaped member having a substantially flat surface area forming one of said abutment surfaces.

align with a corresponding shoulder portion forming one end of each element of said pair of first flange elements when said control head is in said operational position.

12. The apparatus of claim 11 wherein said shoulder portions face in substantially opposite directions around the circumference of the opening in said neck. 

1. Fluid medium dispensing apparatus comprising: a container for storing the fluid medium under pressure and having a neck portion at one end defining an opening; a control head mountable within said opening and having means thereon for sealing the opening, said control head being movable relative to the container between an upper operational position in which said sealing means seals the opening and a lower venting position; at least first and second mutually engagable flange elements connected respectively to the container and to the control head, each of said elements having an abutment surface engagable with the other to limit upward movement of the control head; a pair of radially inwardly extending substantially vertical stop surfaces formed on said container within said neck, said surfaces facing in opposite directions around the circumference of the opening in said neck; a pair of radially outwardly extending substantially vertical stop surfaces formed on said control head, each of said outwardly extenDing stop surfaces being aligned with a corresponding one of said inwardly extending stop surfaces to constrain rotational movement of said control head when said control head is in said operational position.
 2. The apparatus of claim 1 wherein the abutment surface of said first flange element overlies the corresponding abutment surface of said second flange element when the control head is in said operation position.
 3. The apparatus of claim 2 wherein at least one of said inwardly extending stop surfaces is formed as part of said first flange.
 4. The apparatus of claim 3 wherein at least one of said outwardly extending stop surfaces is formed as part of said second flange.
 5. The apparatus of claim 4 wherein one of said flange elements comprises a promontory, the stop surface of said one flange being formed on said promontory and having a portion aligned with the corresponding stop surface of the other of said flange elements when the control head is in said operating position.
 6. The apparatus of claim 5 wherein said promotory is formed on said second flange member.
 7. The apparatus of claim 6 wherein said container comprises a pair of said first flange elements protruding from substantially diametrically opposite positions along the periphery of said neck.
 8. The apparatus of claim 7 wherein said control head comprises a pair of said second flange elements protruding from substantially diametrically opposite positions along the periphery of said control head.
 9. The apparatus of claim 8 wherein each of said flange elements comprises a substantially sector shaped member having a substantially flat surface area forming one of said abutment surfaces.
 10. The apparatus of claim 9 wherein the sector angle of each of said flange elements is substantially the same.
 11. The apparatus of claim 10 wherein each element of said pair of second flange elements comprises one of said promontories located adjacent one end and forming an integral part thereof, a portion of the stop surfaces of each of said promontories being adapted to align with a corresponding shoulder portion forming one end of each element of said pair of first flange elements when said control head is in said operational position.
 12. The apparatus of claim 11 wherein said shoulder portions face in substantially opposite directions around the circumference of the opening in said neck. 